<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>URL Shortener</title>
</head>
<body>
    <h1>URL Shortener</h1>
    <form method="post">
        <label for="long_url">输入长 URL：</label>
        <input type="text" id="long_url" name="long_url">
        <input type="submit" value="缩短">
    </form>
    {% if short_url %}
    <p>缩短后的 URL：{{ short_url }}</p>
    {% endif %}
</body>
</html>
